In some conventional receivers, improvements may require extensive system modifications that may be very costly and, in some cases, may even be impractical. Determining the right approach to achieve design improvements may depend on the optimization of a receiver system to a particular modulation type and/or to the various kinds of noises that may be introduced by a transmission channel. For example, the optimization of a receiver system may be based on whether the signals being received, generally in the form of subsequent symbols or information bits, are interdependent. Signals received may be interdependent signals, that is, signals with memory. For example, NRZI may be used when it is desirable for the receiver to synchronize to the received signal via an embedded clock in the received signal. Accordingly, a received bit in a NRZI modulated transmission may depend on demodulation of the previous bit.
One method or algorithm for signal detection in a receiver system that decodes convolutional encoded data is maximum-likelihood sequence estimation (MLSE). The MLSE is an algorithm that performs soft decisions while searching for a sequence that minimizes a distance metric in a trellis that characterizes the memory or interdependence of the transmitted signal. In this regard, an operation based on the Viterbi algorithm may be utilized to reduce the number of sequences in the trellis search when new signals are received.
However, one drawback may be that a bit-sequence chosen via, for example, the Viterbi algorithm may not satisfy specific constraints of a system. For example, a bit-sequence chosen as the most likely candidate for an application data via a Viterbi algorithm may not satisfy application constraints.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.